Android google maps inside fragment

I know that there are a lot of questions about maps inside a fragment on stackoverflow, but all of them are outdated and are not working for me.. So, I am trying to implement google maps inside a fragment, the map is displayed, but I caot use setMyLocationEnabler(true), or add markers, or anything.. Here's my code:

public class MapFragment extends Fragment {

private SupportMapFragment mSupportMapFragment;

public MapFragment() {
    // Required empty public constructor
}


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    mSupportMapFragment = (SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.location_map);
    if (mSupportMapFragment == null) {
        FragmentManager fragmentManager = getChildFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        mSupportMapFragment = SupportMapFragment.newInstance();
        fragmentTransaction.replace(R.id.location_map, mSupportMapFragment).commit();
    }
    if (mSupportMapFragment != null) {
        mSupportMapFragment.getMapAsync(new OnMapReadyCallback() {
            @Override
            public void onMapReady(GoogleMap googleMap) {
                if (googleMap != null) {
                    googleMap.getUiSettings().setAllGesturesEnabled(true);
                    if (ActivityCompat.checkSelfPermission(getContext(), Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(getContext(), Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                        retu;
                    }
                    googleMap.setMyLocationEnabled(true);
                    LatLng sydney = new LatLng(-34, 151);
                    googleMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
                    googleMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
                }
            }
        });
    }

    // Inflate the layout for this fragment
    retu inflater.inflate(R.layout.fragment_map, container, false);
}

}

My API key is correctly added in the manifest file:

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>

<application

    <meta-data android:name="com.google.android.geo.API_KEY" android:value="-----------------------------------"/>

</application>

And here's the fragment layout:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="mk.com.urban.urbanrider.MapFragment">

<!-- TODO: Update blank fragment layout -->
<FrameLayout
    android:id="@+id/location_map"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    class="com.google.android.gms.maps.SupportMapFragment" />

</RelativeLayout>

I have google play services dependencies in by build.gradle:

dependencies {
compile fileTree(include: ['*.jar'], dir: 'libs')
testCompile 'junit:junit:4.12'
compile project(':volley')
compile 'com.android.support:appcompat-v7:23.4.0'
compile 'com.android.support:design:23.4.0'
compile 'com.android.support:support-v4:23.4.0'
compile 'com.google.android.gms:play-services:8.4.0'
}

I really have no idea what to do next, I've tried everything...